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Stroke Risk

First-Time Catheter Ablation for Atrial Fibrillation Safer Than Ever

For patients with symptomatic A-Fib, catheter ablation is a commonly performed procedure. However, it does have potential complications. As with any procedure, the informed patient needs to know the risk factors.

To determine the most recent complication rates, researchers did a systematic review and pooled analysis of 89 studies from the past 10 years. Their results were published in May 2023.

Research Methods 

EDLINE and EMBASE databases were searched from January 2013 to September 2022 for randomized control trials that included patients undergoing a first ablation procedure using either radiofrequency or cryoballoon.

A total of 89 studies met inclusion criteria. A total of 15,701 patients were included in the current analysis.

By comparison, the complication rate for the common appendectomy is around 18%.

Survey Findings

Vascular complications (i.e., bleeding and clotting) were the most frequent type of complication (1.31%).

The next most common complications were pericardial effusion/tamponade (i.e., fluid buildup around the heart) (0.78%) and stroke/transient ischemic attack (blood clot to the brain) (0.17%).

During the 10-year period of the analysis, procedure-related complication rates were:
• Overall 4.51%
Severe  2.44%

Comparing the earlier 5-year period to the most recent 5-year period, complication rates were:
• Earlier period: 5.31%
• Most recent period: 3.77%.

Over the 2 time periods, mortality rates were stable.

There was no significant difference as to pattern of A-Fib, ablation technique, or ablation strategies beyond the pulmonary vein isolation.

Researchers Conclusions

When you see the term “catheter ablation” it’s shorthand for pulmonary veins ablation (PVA).
Procedure-related complications and mortality rates associated with A-Fib catheter ablation are low.

Complication rates have declined in the past decade (2013-2022).

A significant improvement in the safety of the procedure was observed over the last 5 years (2018-2022).

Neither the type of energy used for ablation nor the creation of additional lesions in addition to the pulmonary veins significantly influenced the procedural complication rate.

Editor's CommentsWhat This Means for A-Fib Patients

One of the drawbacks of these findings from a patient’s perspective it that it doesn’t differentiate between major and minor complications.

All Complications Are Not Equal: For example, vascular complications (such as bruising or bleeding at the catheter insertion points) are usually minor and easily taken care of with no lasting consequences.

More serious complications are:

Tamponade: Blood can bleed into the pericardium sac that surrounds the heart compressing it. Most centers and Electrophysiologists (EPs) are well aware of this and can move swiftly to drain off the extra blood.

Atrioesophageal Fistula: This is a very rare complication (less than 1 in 1000) but one which can kill you. When a catheter makes an RF burn (lesion) near the esophagus, the heat may damage the esophagus wall which can later be eroded by gastric acids allowing blood to leak into the esophagus. Most centers and EPs now take extensive precautions to prevent this. (The new technology, Pulse Field Ablation, virtually eliminates this complication, see Pulsed Field Ablation—Emerging Tech for Atrial Fibrillation)

Stroke: During a catheter ablation you are on heavy-duty anticoagulants so strokes are rare (0.17%). But as with anyone with A-Fib, strokes can occur.

In this analysis of 89 studies the overall major complication rate was very small.

First-Time Catheter Ablation: The bottom line for us patients is that first-time catheter ablation (PVA) is one of the safest procedures you can have in a hospital. (FYI: By comparison, the complication rate for the common appendectomy is around 18%.)

In practice, for most A-Fib patients, the actual risks are so small that it’s safer getting a PVA than not getting one.

A PVA is safe and afterwards certainly feels a lot better than a life in A-Fib and/or a life on antiarrhythmic drugs and anticoagulants. One reason people get a PVA is so that they don’t have to live the rest of their lives on these drugs.

When choosing to have a catheter ablation, make the effort to find high volume operators and experienced hospitals.

Catheter Ablation is Considered a Low-Risk Procedure: Over 1 million catheter ablations are performed annually in the U.S.

The complication rate has continued to decrease.  In this analysis a significant improvement in safety was observed over the last 5 years.

But Beware of Low-Volume Operators: As patients we need to be aware that complications come mostly from low volume operators (those who perform less than 25 ablations a year), and that 81% of all ablations are performed by low volume operators.

This is important! When choosing to have a catheter ablation, make the effort to find high volume operators and experienced hospitals.

Benali K, Khairy P, Hammache N, et al. Procedure-Related Complications of Catheter Ablation for Atrial Fibrillation. J Am Coll Cardiol. 2023 May, 81 (21) 2089–2099.

Bleeding From Anticoagulants—All Anticoagulants are Dangerous

No one likes to take anticoagulants. They are inherently dangerous.

Drug therapy with oral anticoagulants in patients with atrial fibrillation is based on finding the ideal balance of effectiveness versus safety of these drugs.

In real-world clinical practice, bleedings were the most typical and common adverse events from treatment with oral anticoagulants (NOACs). Data from observational studies are an additional source of information for the adverse events (AEs) that come from taking anticoagulants.

Bleedings were the most typical and common adverse events from treatment with oral anticoagulants (NOACs).
One observational study, “ANTEY”, is a study from Russia that followed 186 A-Fib patients taking anticoagulants. The study reported 55 adverse events (AEs). There were 25 serious events, including 4 deaths.

The incidence of bleeding of those treated with NOACs was approximately 8% to 9%. (The bleeding risk with warfarin, was much higher.)

How Anticoagulants Decrease Your Risk of Blood Clots and Stroke

To decrease your risk of blood clots and stroke, anticoagulants hinder the clotting ability of your blood. The result is anticoagulants can cause or increase bleeding. That’s how they work.

In addition, they increase your risk of microbleeds in the brain, hemorrhagic stroke, early dementia, and gastrointestinal bleeding.

“Oral anticoagulants are high-risk medications” (Drs. Witt & Hansen).

Alert to Anyone Taking Anticoagulants

This study from Russia is another Red Flag alert for anyone taking anticoagulants.

It’s like playing Russian Roulette with your health. One out of ten times you’re at risk of a bullet to the brain (i.e., 8%-9% risk of Adverse Events when taking anticoagulants).

None the Less, Anticoagulants Do Reduce Your Chance of Stroke

But in spite of the possible negative effects of anticoagulants, if you have A-Fib and are at real risk of stroke, anticoagulants do work.

You’re no longer 4–5 times more likely to have an A-Fib (ischemic) stroke. Taking an anticoagulant to prevent an A-Fib stroke also may give you peace of mind.

If You Have A-Fib, Can You Safely Stop Taking Anticoagulants?

Never just stop taking your anticoagulant or reducing the dosage. That’s a decision for you and your doctor.

Yes! The best way to deal with the increased risk of stroke and side effects of anticoagulants is to no longer need them.

Here are three options:

#1 Alternative: Get rid of your A-Fib

As EP and prolific blogger Dr. John Mandrola wrote: “…if there is no A-Fib, there is no benefit from anticoagulation.”

Action: Request a catheter ablation procedure. Today, you can have an ablation immediately (called ‘first-line therapy’). You don’t have to waste a year on failed drug therapies. See Catheter Ablation Reduces Stroke Risk Even for Higher Risk Patients

#2 Alternative: Close off your Left Atrial Appendage (LAA)

The Left Atrial Appendage is where 90%-95% of A-Fib clots originate. Close off your LAA and you may no longer need to take an anticoagulant.

Action: Request a Watchman occlusion device. The Watchman device is inserted to close off your LAA and keep clots from entering your blood stream. See Watchman Better Than Lifetime on Warfarin

#3 Alternative: Consider non-prescription blood thinners

Ask your doctor about your CHA2DS2-VASc score (a stroke risk assessor). If your score is a 1 or 2 (out of 10), you are at low risk of having a stroke. You may not need to take an anticoagulant at all.

Action: Ask your doctor if you could take a non-prescription approach to a blood thinner. Perhaps you can benefit from an increase in natural blood thinners such as turmeric, ginger, vitamin E or, especially, the supplement Nattokinase. See FAQ: “Are natural blood thinners as good as prescription blood thinners?”  (Only change your medication under your doctor’s supervision.)

What this Means for A-Fib Patients

Bleeding from taking anticoagulants is a serious side effect. Drug therapy with oral anticoagulants  is based on finding the ideal balance of effectiveness versus safety of these drugs.

Perhaps the best balance may be to avoid needing anticoagulants in the first place:

Your options: Seek your A-Fib cure, i.e., get rid of your Atrial Fibrillation. Reduce your risk of stroke by closing off your Left Atrial Appendage. Or seek a non-drug natural blood thinner option to taking an anticoagulant.

• Martsevich, S. Y. et al. Analysis of Adverse Events in the Treatment of Patients with Non-Valvular Atrial Fibrillation with Oral Anticoagulants: Data from the “ANTEY” Observational Study. Pharmaceuticals. 2022, 13, 1209, MDPI.

• Witt, Daniel W. and Hansen, Alisyn L. New Oral Anticoagulants Can Require Careful Dosing Too. by Scott Baltic. Editorial, Medscape/Reuters Health Information, December 29, 2016.


A-Fib Patients Study: After Brain Hemorrhage, Back on Anticoagulation?

Sometimes I just can’t understand some of the research studies done about Atrial Fibrillation such as this one. I can not wrap my head around this recent study from the Netherlands (APACHE-AF).

They studied A-Fib patients who survived intracerebral hemorrhage after being treated with anticoagulation for atrial fibrillation. Their hemorrhagic stroke was “anticoagulant-associated”. Seven to 90 days after their hemorrhage, patients were either put back on anticoagulation (50 patients) or avoided anticoagulation.

WHAT?! How can you put someone back on an anticoagulant which probably caused their hemorrhagic stroke in the first place?
These researchers certainly knew the alternative options to taking anticoagulants.

This study was done at 16 hospitals in the Netherlands but was nevertheless very small. Most patients who did suffer a hemorrhagic stroke either died or were severely disabled. Few survived. That’s why there were so few patients in the study.

Further Damage From Anticoagulation

Not surprisingly, after a minimum follow-up of 6 months (a very short follow-up), 26% of the apixaban group had non-fatal strokes or vascular death. The patients on antiplatelet therapy (26) or no anticoagulation didn’t do very well either.

The researchers themselves concluded, “Patients with atrial fibrillation who had an intracerebral hemorrhage while taking anticoagulants have a high subsequent annual risk of non-fatal stroke or vascular death.”

Did I Miss Something?

How can you put someone back on an anticoagulant, even Eliquis, when anticoagulants probably caused their hemorrhagic stroke in the first place? This seems both ethically wrong and wrong-headed.

Did I miss something important? If anyone wants to share their view of this study with me, send me an email.

Schreuder, F. et al.  Apixaban versus no anticoagulation after anticoagulation-associated intracerebral haemorrhage in patients with atrial fibrillation in the Netherlands (APACHE-AF): a randomized, open-label, phase 2 trial. The Lancet Neurology, November 2021. DOI:

2022 AF Symposium: Procedural Anticoagulation with LAA Closure Devices for A-Fib Patients

In this report from the 2022 AF Symposium, Dr. Luigi Di Biase of the Albert Einstein College of Medicine, Bronx, NY gave a presentation on “Peri and Post Procedural Anticoagulation with LAA Closure Devices―An Evolving Story”.

In particular, he is talking about the Watchman occlusion device to close off an A-Fib patient’s Left Atrial Appendage. His focus is on the anticoagulation protocol following the procedure involving, that is, the drug regime for patients in the months afterward. e.g., DOACs, aspirin and clopidogrel.

This is a short report, a quick read, go to Procedural Anticoagulation with LAA Closure Devices―An Evolving A-Fib Story.

(Finally) A Head-to-Head Comparison of Anticoagulants for A-Fib: Eliquis vs Xarelto

The most commonly prescribed direct-acting anticoagulants (DOACs) for A-Fib patients are Eliquis (generic name: apixaban) and Xarelto (generic name: rivaroxaban).

Direct-acting anticoagulants (DOACs) were introduced in the early 2010s, but most of the testing has been against warfarin, not against other DOACs. Finally, thanks to the researchers of two retrospective studies, A-Fib patients now have a head-to-head comparison of Eliquis versus Xarelto.

Study 1: Stroke and Bleeding Risks

A recent retrospective study (Fralick, M. et al) looked at 6 years of prescription data for atrial fibrillation patients from the Nationwide Healthcare Claims Database (NPIC). A-Fib patient group sizes were matched (39,351 each). Mean age was 69 years, 40% were women and follow up was 288–291 days.

Significant Findings 

Eliquis patients had significantly lower incidence of major bleeding (12.9 vs 21.9 events-per-1K-person-yrs.)

1. Eliquis patients had significantly lower rates of stroke or systemic embolism (6.6 vs 8.0 events per 1000 person-years) compared to Xarelto.

2. Eliquis patients had a significantly lower incidence of major bleeding, defined as gastrointestinal bleeding or intracranial hemorrhage (12.9 vs 21.9 events per 1000 person-years).

Researchers Conclusion (Fralick, M. et al): In routine care, adults with atrial fibrillation prescribed apixaban had a lower rate of both ischemic stroke or systemic embolism and bleeding compared with those prescribed rivaroxaban.

Study 2: Stroke and Bleeding Risks

A second retrospective study (Ray, W. et al) looked at 581,451 atrial fibrillation patients 65 years or older who were enrolled in Medicare from 2013–2018. A-Fib patient group sizes were Rivaroxaban, 227,572 and Apixaban, 353,879. Follow up was for 4 years, through November 30, 2018. Mean age was 77.0 years; 50.2% were women (291 966).

Significant Findings 

Xarelto had substantially more nonfatal extracranial bleeding (39.7 vs 18.5 events-per-1K-person-yrs.)

1. Xarelto patients had more hemorrhagic events including fatal extracranial bleeding (1.4 vs 1.0 per 1000 person-years)

2. Xarelto had more nonfatal extracranial bleeding (39.7 vs 18.5 per 1000 person-years)

3. Xarelto had more fatal ischemic/hemorrhagic events (4.5 vs 3.3 per 1000 person-years)

4. Xarelto had more “total mortality” (44.2 vs 41.0 per 1000 person-years)

Researchers Conclusions and Relevance (Ray, W. et al):  Among Medicare beneficiaries 65 years or older with atrial fibrillation, treatment with rivaroxaban compared with apixaban was associated with a significantly increased risk of major ischemic or hemorrhagic events.

Eliquis vs Xarelto…and the Winner is…

Eliquis (apixaban)! In routine care, Eliquis was found to be both more effective and safer than Xarelto.

As patients, we should pay particular attention to the fact that Eliquis had significantly lower incidence of major bleeding (gastrointestinal bleeding or intracranial hemorrhage) than Xarelto (12.9 vs 21.9 events). And that Xarelto had increased nonfatal extracranial bleeding (39.7 vs 18.5 events) compared to Eliquis.

These differences in bleeding weren’t just “statistically significant” but were really alarming. Major, red flag warning important. Particularly for older people who are more prone to bleeding problems.

Alert: There is anecdotal evidence that some healthcare insurers are pushing patients to switch from Eliquis to Xarelto, despite the above research.

Be Your Own Best Patient-Advocate

Whether or not to take anticoagulants and which one is one of the most difficult decisions you and your doctor must make.

All the results cited above were “significant” and should be taken into account when choosing an anticoagulant.

If you are taking Xarelto, you should talk with your doctor about switching to Eliquis.

Learn all you can about your health conditions. A well-informed patient is welcomed by your doctors and healthcare caregivers. (If not, consider changing doctors.)
• Fralick, M. et al. Effectiveness and Safety of Apixaban Compared With Rivaroxaban for Patients With Atrial Fibrillation in Routine Practice: A Cohort Study. APC Journals, Annals of Internal Medicine. April 7, 2020.

• Ray, W. et al. Association of Rivaroxaban vs Apixaban With Major Ischemic or Hemorrhagic Events in Patients with Atrial Fibrillation. JAMA. 2021;326(23):2395-2404. doi:10.1001/jama.2021.21222

• Dressler, D. et al. Apixaban Might Be Safer and More Effective Than Rivaroxaban for Atrial Fibrillation. NEJM Journal Watch, Ann Intern Med 2020 Mar 9.

• The FH NPIC (National Private Insurance Claims) database. Includes information found on medical and dental claim forms for billions of services billed through private health insurance. 

• Dawwas, G.K. et al. Apixaban Versus Rivaroxaban in Patients With Atrial Fibrillation and Valvular Heart Disease—A Population-Based Study. Annals of Internal Medicine, 18 October 2022.


2022 AF Symposium: The LOOP Study–Implications for Clinical Practice

Last week, I published my Overview of the 2022 AF Symposium held in January in New York City. You can find it on my page, My Summary Reports Written for Atrial Fibrillation Patients.

The LOOP Study – Implications for Clinical Practice and Future Trials” was presented by Dr. Andrea Russo of Cooper University Hospital in Camden, New Jersey.

Dr. Andrea Russo

Dr. Andrea Russo

A-Fib Strokes More Dangerous: Dr. Russo described how one-third of strokes are due to A-Fib. And these strokes are more severe and debilitating than those not associated with A-Fib. Many were not diagnosed with Atrial Fibrillation until after they had a stroke or heart attack.

The LOOP Study Research: The researchers posed the questions: Is all A-Fib is worth seeing or worrying over? “Does all detected A-Fib require anticoagulation?” Is A-Fib lasting more than 6 minutes but less than 24 hours duration, really a threat?

From 4 centers in Denmark, study patients received the Medtronic Reveal LINQ LOOP Implantable Recorders (ILR), the Reveal LINQ to investigate…. continue reading The Loop Study.

A-Fib Stroke Risk: The LOOP Study–Implications for Clinical Practice and Future Trials

2022 AF Symposium

The LOOP Study–Implications for Clinical Practice and Future Trials

Dr. Andrea Russo of Cooper University Hospital in Camden, New Jersey gave a talk on “The LOOP Study – Implications for Clinical Practice and Future Trials”.

Dr. Andrea Russo

Dr. Andrea Russo

A-Fib Strokes More Dangerous

She described how one-third of strokes are due to A-Fib. And these strokes are more severe and debilitating than those not associated with A-Fib.

Asymptomatic A-Fib may not be diagnosed until after someone has a stroke or heart attack. Dr. Russo described how previous studies defined “device detected A-Fib” as lasting more than 6 minutes but less than 24 hours duration without a prior diagnosis of A-Fib.

The LOOP Study Research

From 4 centers in Denmark, the LOOP Implantable Recorder Study investigated whether anticoagulation can prevent stroke in patients with high risk of stroke.

Participants: In the study, 318 patients, with no prior A-Fib, were over 70 years old (average age was 75 or over) and had at least one risk factor for stroke. They each received an implantable loop recorder (ILR), the Reveal LINQ (by Medtronic).

The control group received standard care (an annual interview with a study nurse and typical interactions with the participant’s general practitioner.)

Patients were monitored and followed for 2-3 years (medium follow-up 64 months).

Study Results

For both groups, the primary outcome was stroke or systemic embolism. Anticoagulation was recommended if someone had A-Fib for 6 minutes or longer.

A-Fib was detected in 32% of the implanted loop recorder group while in only 13% of the control group who received usual care.

There was no significant difference between the groups in major bleeding and hemorrhagic stroke.

Of the LOOP group, 4.5% suffered a primary outcome (stroke or embolism) compared to 5.6% of the control group.

Short Duration A-Fib Not a Risk

The researchers posed the question: Is all A-Fib worth seeing or worrying over? “Does all detected A-Fib require anticoagulation?” Is 6 minutes of A-Fib really a threat?

Dr. Russo cited other studies such as ASSERT where 6-24 hours of A-Fib wasn’t significant as a risk of stroke, whereas over 24 hours duration was. (See my report: How Long Does It Take for an A-Fib Clot to Form? The ASSERT Clinical Trial )

Researchers also asked: What other considerations should be examined? What about A-Fib burden?

Editor's Comments about Cecelia's A-Fib storyEditor’s Comments

Dr. Russo is going against the grain of conventional A-Fib thought by suggesting that 6 minutes of A-Fib is not a serious threat or risk of developing an A-Fib stroke.

If you only have an occasional, short episode of A-Fib, you may not need an anticoagulant. If your doctor insists that you take an anticoagulant, it might be time to get a second opinion.

Remember that anticoagulants are considered high risk drugs. They should only be prescribed if there is a real risk of stroke.

If you find any errors on this page, email us. Y Last updated: Friday, February 25, 2022

Return to 2022 AF Symposium Reports

Anticoagulation CHA2DS2-VASc Clinical Guidelines to Prevent A-Fib Stroke

by Steve S. Ryan, PhD

Background: “Guideline for the Management of Patients With Atrial Fibrillation” is official policy of the American College of Cardiology (ACC) and the American Heart Association (AHA). For clinical practices, they serve as a foundation for the delivery of quality cardiovascular care.

When you develop Atrial Fibrillation, you are at increased risk of clots and stroke. To help A-Fib doctors determine your risk for stroke or heart attack, they use the CHA2DS2-VASc assessment tool.

Not all doctors agree with its recommendations, some find serious fault with it. One of them is Dr. Mintu Turakhia, Professor of Cardiovascular Medicine at Stanford University.

The original 2001 CHA2DS2 assessment tool was revised in 2012 to the current CHA2DS2-VASc.

“CHA2DS2-VASc is a stain on our field.” This statement by Dr. Mintu Turakhia at Stanford Un., CA, was made at the 2022 AF Symposium. A bold statement. This quote reflects the mixed feelings doctors have about these recommendations from Guidelines for the Management of Patients with Atrial Fibrillation.

But for better or worse, our doctors have to live with them. These Guidelines have become, in effect, the law of the land.

As patients we need to understand how these Guidelines work and what they mean for us when we have A-Fib.

CHA2DS2-VASc Risk Assessment

Here’s the CHA2DS2-VASc Risk Assessment tool. Try it—add up your own risk score.

Risk FactorRisk Score
Age 65-74 “A”

Age over 75 “A2”



Female sex “Sc”+1
CHF (Congestive Heart Failure) “C”+1`
Hypertension (Uncontrolled High Blood Pressure) “H” (Over 140/90)+1
Stroke/TIA “S2”+2
Vascular Disease (Heart Attack, etc.) “V”+2
Diabetes “D”+1
Total score:

How’d you do? According to the Guidelines, any risk score higher than zero for men and 1 for women dictate you should be on an anticoagulant.

Did you notice…that just being a 65-year-old female (2 pts.) automatically rates you at risk of stroke? Not taken into account were the patient’s fitness, level of activity, or even a family history of stroke. Is this an accurate assessment of stroke risk or is something lacking?

Beware: Guidelines “Recommend” Almost Everyone with A-Fib be on Anticoagulation

Only people with a risk score of 0 (males) and 1 (females) are considered low risk patients. What this means in practice is that almost everyone with A-Fib is supposed to be on an anticoagulant for life.

In addition, Dr. Gregory Lip, who was instrumental in developing the CHA2DS2-VASc guidelines, states that even a risk factor of 0 can “identify those who would still substantially benefit from oral anticoagulation.”

In other words, even those with a risk factor of 0 may be put on anticoagulants. (Really?)

Gender as a Risk of Stroke: In the Guidelines, a woman with A-Fib is automatically given one point on the stroke risk scale simply because of being female, no matter how healthy she may be otherwise. (“Sc” stands for sex i.e., female gender.)

(I find that this is not justified by research; Is this a not-very-subtle form of gender bias? See my post: Israeli Study Contradicts Recent CHA2DS2-VASc Guidelines.)

The Exception: controlled Hypertension: If you have hypertension which is controlled (by for example taking a drug like lisinopril) and is under 140/90, you are not considered to have a risk factor for stroke.

Anticoagulants are High Risk Drugs

Unlike what you hear in today’s advertising, anticoagulants are not like taking vitamins. They work by increasing your risk of bleeding. The Guidelines do not discuss that “Oral anticoagulants are high risk medications.”

Unlike what you hear in today’s advertising, anticoagulants are not like taking vitamins.

Dr. John Day describes his patient (and personal friend) Bob who, was on anticoagulation for 10 years. Basically he became a vegetable with early dementia. He remained on an anticoagulant even though he had been A-Fib free after a catheter ablation. (Read the story in my post: The Risks of Life-Long Anticoagulation Therapy)

But because of these guidelines, many more people will be put on anticoagulants, particularly women, and develop other health problems. (Read more: Anticoagulants Increase Risk of Hemorrhagic-Type Strokes ).

Added Motivation to Prescribe Anticoagulants

One of the reasons doctors prescribe anticoagulants at the drop of a hat is the risk of a malpractice lawsuit.

The Guidelines are “in effect” dictates. If a doctor doesn’t follow these guidelines, and a patient has a stroke, that doctor is almost guaranteed a losing malpractice lawsuit. The first thing a trial lawyer will point out to an arbitrator or jury is that the doctor didn’t follow current guidelines.

Anticoagulation: Newer Interpretations of the Guidelines

Reflecting the absurdity of one point for female gender, today’s anticoagulation “recommendations” (dictates) are the same for men with 1 point as for women with 2 points.

(It sounds like the writers of the Guidelines recognize their error and bias against women but won’t actually change the guidelines so as not to lose face and acknowledge they were wrong.)

Female Patients: Is Your Doctor Aware of this Modification? Many doctors are not aware of this new interpretation of the guidelines and automatically put women with A-Fib on anticoagulants for life, without regard to anything else.

How Medical Guidelines can Create Pharma Financial Windfall

Medical Guidelines can have an immense impact on the lives of patients. And an immense boost to revenue for the pharmaceutical industry, often overnight.

Overnight nearly half of US adults were suddenly classified as having hypertension.

For instance, in 2017, new guidelines for the management of high blood pressure were issued by the ACC and AHA. The threshold for hypertension was lowered from 140/90 mm Hg (or higher) to 130/80 mm Hg.

Overnight nearly half of US adults were suddenly classified as having hypertension. This means doctors would be prescribing a lot more medications, to a lot more patients. What a boom to the sales of thiazide diuretics, ACE inhibitors, ARBs, and calcium channel blockers.

This one change in the medical guidelines was a financial windfall for drug companies and represents a huge increase in customers (many for a lifetime). Doctors complained, patients complained, but not the drug companies.

Don’t Just be a Number on a Risk Assessment Tool!

To take an anticoagulant or not (and, if so, which one) is one of the most important decisions you and your doctor will make.

Don’t just be a number on a risk assessment tool. Educate yourself. Become your own best Patient Advocate.

Start with the posts I’ve mentioned above. Arm yourself with an understanding of anticoagulants and your risk of clots and strokes. Then you need to intelligently discuss this decision with your doctor.

• Lip, Gregory CHA2DS2-VASc Score for Atrial Fibrillation Stroke Risk. URL

• Baltic, S. New Oral Anticoagulants Can Require Careful Dosing Too. Medscape/Reuters Health Information. December 29, 2016. (Quote: Dr. Daniel M. Witt and Dr. Alisyn L. Hansen of the University of Utah College of Pharmacy.) URLL:

• AHA/ACC/HRS 2019 Focused Update of the 2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation. DOI: 10.1016/j.jacc.2019.01.011

• Bakris, G, Sorrentino, M. Redefining Hypertension — Assessing the New Blood-Pressure Guidelines. N Engl J Med 2018; 378:497-499. DOI: 10.1056/NEJMp1716193


Who’s at Higher Risk of a Recurrent A-Fib Stroke?

You’ve had an A-Fib stroke—and you survived—hoorah! Now you wonder…am I more prone to a recurrent stroke? The answer may lie with how often your A-Fib episodes occur (i.e., paroxysmal versus persistent/permanent).

A recent observational research study from Japan posed this question:

In patients with a history of ischemic stroke and atrial fibrillation (A-Fib), is there a difference in the risk of future stroke between those with paroxysmal versus permanent atrial fibrillation?

What’s the Risk of a Recurrent A-Fib Stroke?

The SAMURAI-NVAF study included 1,192 A-Fib patients who had suffered an acute or ischemic stroke (where a clot blocks blood flow to the brain) and followed them for around 1.8 years.

Study patients were hospitalized within 7 days of stroke between April 2011 and March 2014 at 18 Japanese stroke centers. The average age was 77.7 ± 9.9 years, 44% were women, and 63.6% had persistent A-Fib.

Findings: Patients with Persistent A-Fib at Higher Risk of Recurrent Stroke

The researchers found a higher risk of ischemic stroke (or systemic embolism) in those with persistent A-Fib. Persistent patients also had higher rates of both ischemic strokes and transient ischemic attacks (TIAs).

Comorbidities means presence of two or more diseases or medical conditions in a patient.

Patients with persistent A-Fib were in general less healthy. They were more likely to have comorbidities: congestive heart failure, liver problems, higher alcohol use, and more disability after the first stroke.

Patients with paroxysmal A-Fib were associated with increased odds of “functional independence” 3 months after their A-Fib stroke (i.e., less likely to be disabled after the stroke).

Why More Stroke Risk When Persistent? The researchers noted that patients with persistent A-Fib have larger Left Atrial Appendage (LAA) size and more severe blood flow problems (lower LAA ejection fraction). … Continue reading this report…->

How Long Does It Take for an A-Fib Clot to Form? The ASSERT Clinical Trial

Background: Of A-Fib stroke patients, 23% die and 44% suffer significant neurologic damage. This compares to only an 8% mortality rate from other causes of stroke.

How Long Does It Take for a Clot to Form? Some doctors say it only takes around 5 minutes for an A-Fib clot to form and cause a stroke that kills you.

This is generally not accepted thinking among Cardiologists and Electrophysiologists (EPs). The ASSERT clinical trial gives us some insights.

How Do Clots Form and Cause Strokes?

Clots aren’t formed instantaneously. It takes a while for blood to pool and form a clot of significant size. If you have a ten-minute attack of A-Fib, for example, it’s unlikely a clot/stroke will develop.

When someone is in A-Fib, blood is not being effectively pumped out of the left atrium. There are spots where blood can pool such in as the Left Atrial Appendage (LAA). This pooled blood can form a clot.

When the left atrium again beats normally, it can push this clot downstream into the left ventricle and into the bloodstream. From there, the clot can travel into the brain causing an ischemic (blocking) stroke.

Patients in permanent A-Fib are at higher risk of clots and stroke. But not in just a few minutes.

(Another risk of A-Fib is a hemorrhagic stroke when a blood vessel bursts, causing bleeding in the brain.)

ASSERT stands for “Asymptomatic Atrial Fibrillation and Stroke Evaluation in Pacemaker Patients and the Atrial Fibrillation Reduction Atrial Pacing Trial”.

The ASSERT Study

The ASSERT clinical trial is a fascinating study with data collected by pacemakers and defibrillators (ICDs). Researchers looked at pacemaker patients and their risks of developing Silent A-Fib and stroke. Their primary question was: Do Pacemakers Prevent A-Fib?

A secondary benefit of the study is the A-Fib patient data collected. In particular, when and how long it takes for A-Fib patients to develop a serious risk of stroke.

The study gives us insight into when and how long it takes for A-Fib patients to develop a serious risk of stroke.

Study Description: The ASSERT study enrolled 2,580 patients, 65 years of age or older, with hypertension and no history of A-Fib, in whom a pacemaker or defibrillator (ICD) had recently been installed.

The pacemaker and ICD devices were programmed to detect silent A-Fib (i.e., Subclinical Atrial Tachycardia [SCAF]) when the heart rate reached 190 beats or more per minute lasting more than 6 minutes. The devices were checked at a clinical visit 3 months later. These patients were then followed up for around 2.5 years.

How Long in Silent A-Fib to Significantly Increase Clot/Stroke Risk

In the ASSERT study they found that it took more than 17.72 hours to significantly increase the annual stroke risk. The results of all patients are divided into four quartiles:

Duration Quartile: Time in Silent A-FibAnnual Stroke Risk
≥ 0.86 Hours1.23 %
0.87-3.63 Hours0 %
3.64-17.72 Hours1.18 %
˃ 17.72 Hours4.89 %

Researchers found the annual stroke risks for patients with Silent A-Fib for less that 17.72 hours were similar to the stroke risk for healthy people (which is considered to be 1%).

The ASSERT study basically said that it takes around 24 hours of silent A-Fib to develop a serious clot/risk of stroke (on average 3.1%).

Contrary Interpretation: In a later analysis of the same ASSERT study by Van Gelder (2017), patients with lengths of Subclinical Atrial Tachycardia (SCAF) from 6hrs to 24hrs were not significantly different from patients without SCAF.

Similar Trial Results: The TRENDS study, a prospective, observational study, also used implanted devices and found similar results as the ASSERT study.

Do Pacemakers Work to Prevent A-Fib?

The primary question of the ASSERT study was: Do Pacemakers Prevent A-Fib?
Finding: Pacemakers (continuous overdrive pacing) “does not prevent clinical atrial fibrillation.”

Editor’s Comments

Editor's Comments about Cecelia's A-Fib storyShorter Episodes of A-Fib Not Generally Dangerous: Despite studies such and ASSERT and TRENDS, we still need many more studies on how long it takes for a clot/stroke to form. Probably the most useful data to date does come from the ASSERT study where it took around 24 hours of silent A-Fib before clot/stroke risk was significantly increased.
People with shorter episodes of A-Fib or silent A-Fib, such as may occur after a successful catheter ablation, may not need to be on anticoagulants at all. Remember that anticoagulants are high risk drugs that shouldn’t be taken unless there is a real risk of stroke.

The general consensus is that A-Fib clots/strokes take around 24 hours to develop. In a popular article in Bottom Line Health, Dr. Antonio Gotto, cardiovascular disease specialist at Weill Cornell Medical College in New York City, says it takes one day for a clot to form.

Resources for this article

• Healey, J.S. et al. Subclinical Atrial Fibrillation and the Risk of Stroke. The New England Journal of Medicine 2012; 366:120-129. DOI: 10.1056/NEJMoa1105575

• Glotzer, T. V. et al. The Relationship Between Daily Atrial Tachyarrhythmia Burden From Implantable Device Diagnostics and Stroke Risk―The TRENDS Study. Circulation: Arrhythmia and Electrophysiology, August 4, 2009. 2009;2:474-480. doi: 10.1161/CIRCEP.109.849638

• Gotto, Jr., Antonio M. Bottom Line Health, Vol 26, November 2012, p. 4.

• Van Gelder, I.C. et al. Duration of device-detected subclinical atrial fibrillation and occurrence of stroke in ASSERT. European Heart Journal, Volume 38, Issue 17. 1 May 2017, Pages 1339-1344,

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